Because of
their three-pronged grasping claw configurations, oviraptors were named egg
thieves, but the dinosaurs reputation has in recent years shifted
from egg-stealing to egg-laying. And a new fossil from China illustrates exactly
how some of the species in the group laid their eggs.

The left egg of a pair found inside an
oviraptor has led to some new ideas on how the dinosaur procreated. (The shells
blue color is not original.) Image courtesy of Yen-nien Cheng.

A team of paleontologists, led by Tamaki Soto of the Canadian Museum of Nature
in Ottawa, examined the pelvis of a female oviraptor that contained two immature
eggs inside the body cavity. Each rough-textured egg is about the same size
and shape as a pineapple, seated pointy-end up, and the two eggs similarity
in size indicates that they were probably the same age.

The pairing indicates that the dinosaur, which is related to theropods, the
group thought to be modern birds ancestors, had two working oviducts 
as modern crocodiles do  but, like birds, only produced one egg at a time
from each. Reporting in the April 15 Science, the authors say that the
pointed eggs and their position in the animals pelvis also indicate that
the females may have laid neat, multilayered, ring-shaped clutches
of eggs that they built from the centers of their nests.